Internal-combustion device



A ril 26, 1949. F. N. BA RD 2,468,020

INTERNAL-COMBUS'IIQN DEVICE Filed uamh- 28. 1946 4' sheets-sheet 1 April26, 1949. -BARD 2,468,020

INTERNAL-COMBUSTION DEVICE File d March 2a, 1946 4 Sheets-Sheet 2 April26, 1949. F. N BARD 2,468,020

I INTERNAL-COMBUSTION DEVICE" Filed March 28,, 1946 4 SheetsSheet 4 1770677752".- rzc ((5 WWW,

prises the main body Patented Apr. 26, 1949 UNITED STATES PATENT orricaINTERNAL-COMBUSTION DEVICE Francis N. Bard, Highland Park, 111.Application March 28, 1946, Serial No. 657,650

8' Claims. (Cl. 123-449) This invention relates to an internalcombustion device, and more particularly to an internal combustionpercussive device of the free-piston type and to ignition means thereforincluding a magneto.

Internal combustion hammers of the free-piston type have no crank shaftand, because of this, and because of the terrific vibration present insuch a hammer, it has heretofore been considered impossible to use amagneto for generating the ignition spark. I have devised, and am heredisclosing, magneto and ignition arrangements which are capable ofoperation by means other than a rotating crank shaft, which are properlytimed and related to piston movement despite the absence of a crankshaft, and which are sufficiently rugged in construction to withstandthevibration present in a type.

This application is one of two copending companion applications relatingto magneto ignition of an internal combustion hammer, my other companionapplication being Serial No. 657,649, filed March 28, 1946.

Various features and advantages of this invention will be apparent fromthe following specification and the drawings, in which:

Figure 1 is a sideelevational view, partly in vertical section, of afree-piston internal combustion hammer incorporating one embodiment ofmy inventions; Figure 2 is an enlarged view of the magneto and actuatingassembly and associated hammer parts, partly in vertical section andpartly in' side elevation; Figure 3 is a horizontal sectional view alongthe line 3-3 of Figure 2; Figure 4 is a horizontal sectional view alongthe line 4-4 of Figure 2; Figure 5 is a fragmentary vertical sectionalview along the line 5-5 of Figure 4, with the rollermovementschematically illustrated, Figure 6 is a schematic view showing theignition circuit; and Figure 7 is a partial vertical sectional viewinternal combustion hammer including a modified embodiment of myinventions.

.The internal combustion percussive device with which I am hereconcerned is of a type providing a self-contained gasoline powereddevice for such purposes as pavement breaking, rock drilling, tamping,and thelike. The cylinder l0 comportion of the device and has apiston-hammer ll freely reciprocable therein, being driven downwardly bythe explosion of a combustible charge thereabove and being returned bythe action of a return spring assisted by rebound. Hammers of thisgeneral type, but

hammer of the free-piston of the upper end of an with battery ignition,have been made and sold for some years by my company, and thedescription of the general principles of such hammers and of theiroperation will be kept brief since reference may be made to issuedpatents to supplement the present disclosure if desired, as for ekampleMould Patents 1,868,754 and 1,997,072 and Charles Patents 2,180,034 and2,275,285, these being merely representative examples of the many issuedpatents on such hammers.

Briefly to describe the operation of the hammers here disclosed inFigures 1-5, gasoline in a tank I2 is mixed with air in carburetor l3and delivered to the chamber l4 beneath the piston, where it is partlycompressed by the downward stroke thereof. Near the bottom ofthe'working stroke of the piston the charge'is transferred from thislower space to the combustion space above the piston, at the top of thecylinder [0, through transfer passages which preferably includepassageway portions in the piston II and the portion IS in the cylinderID. The combustible charge thus provided in the upper end of thecylinder is then further compressed on the up ward stroke of the piston,effected primarily by the return spring l6, and at a proper time withrespect to piston movement this charge is ignited by causing a spark tojump across the electrodes of the spark plug ll. Combustion ofthischarge drives the piston downward on its working stroke, thelowerend of the piston eventually striking the top of the anvil It in theanvil housing l9 and the blow thus being transmitted to the tool 20. As

-port 2|,

the piston nears the lower end of its travel the burned gases aredischarged through the exhaust a fresh charge transferred to the spaceabove the piston, and the cycle of operation repeated.

Handles 22 and 23- are provided to enable a workman to spot the tool ina desired working point, to maintain the hammer in operative positionduring working thereof, and to lift the hammer between operations.Starting is accomplished by manually depressing the starting rod 24,normally biased to the position shown by the spring 25, until the pistonH is near the lower end of its travel, then releasing it, then againpushing down on the starting rod and releasing it, an explosion takingplace as soon as a charge has been drawn into the sub-piston compressionspace and transferred to the combustion space above the piston. Themeans for providing ignition of the combustible charge in properly timedrelation to piston movement and in a manner obviating the necessity forcables. storage batteries, and the like, comprises the improvement towhich this and my companion application are directed, and these will nowbe more particularly described.

Referring now more particularly to Figures 2-5, inclusive, a magnetoidentified in general as A will be seen to be mounted on the side wallof the cylinder I, this magneto comprising as its principal parts anouter permanent magnet or pole assembly 26, a rotatably or oscillatablymovable armature member or rotor 21, and a coil 28 wound therein, thiscoil comprising a primary 28a and a secondary 28b in accordance with thepractice followed in more conventional rotary magnetos.

The rotor 21 of the magneto in this case is rigidly mounted on a rotorshaft 29 having its axis vertical (1. e., parallel to the axis of thepiston II) The actuating means for the magneto includes a member 30rigidly mounted on and keyed to the lower end of the shaft 29, thismember 30 being mounted in an appropriate slot lfla in the side wall of'the cylinder, and having its inner end extending into a vertical slotIla in the piston. The inner end'of the member (i. e., the end lying inthe slot I la in the piston) is provided with a roller 3|. The pistonhas pivotally mounted in its side wall in the slot Ila a do or member 32so mounted as to have pivotal movement about the pin portion 320. and tohave this movement limited to about 15 or 20 by the pin 32b in the smallarcuate slot llb in the wall of the piston. The member 30, and thus theshaft 29, are normally biased to a central position by biasing meansbest seen in Figure 4 and comprising the axially movable round headedpins 33 and 34 urged against the side of the member 30 by the similarsprings 35 and 36.

Referring now more particularly to Figure 5, it will be seen thatdownward movement of the piston results in relative movement between itand the roller 3| which causes such roller 3| to be deflected to theleft as shown in various dotted line positions, the upper end of themember 32 being pivoted to the farthest right limit of its movement,referring to the particular position of the parts as viewed in Figure 5,this position being shown in dotted lines. While the member 32 ispreferably not quite vertical in this position, it is provided with atapered left-hand edge near its upper end, as shown, so that the latterpart of the relative movement between the piston and the roller 3| isstraight until the roller passes over the upper tip of the member 32,whereupon the member 32 drops to the left and downwardly to the positionshown in full lines in Figure 5-. Upward movement of the piston on itsreturn thereupon deflects the roller 3| to the right (again speaking asviewed in Figure 5), the positions of the roller 3| during such upwardmovement of the piston being shown 'in dotted lines to the right of themember 32, which will be understood to now be in full line position.When the piston has moved up to near the end of its stroke, the roller3| suddenly takes a rather sharp and quick movement to the left beneaththe member 32 under the influence of the spring 36, the roller no longerbeing held to the right by the member 32. This sudden spring urgedmovement of the roller 3|, the member 30 on which it is mounted and therotor shaft 29 of the magneto is more rapid than could be effected by acam shoulder on the piston without pounding the parts to pieces underthe very high speed of operation in a hammer of this type, usually inthe order of 4 1500 reciprocations per minute of the piston. Thisrelatively rapid although angularly small movement of the rotor tends tochange the flux conditions through the rotor quite rapidly.

Referring now more particularly to Figures 3 and 6, the outer poleconstruction of the rotor is such that it is provided with two poles ofoD- posite polarity, as for example a pole 26a of north polarity and apole 26b of south polarity. In the initial position of the arm 30,slightly to the left of the central position (i. e as shown in Figure 4)the armature 2'! stands in a position slightly counter-clockwise of theneutral position shown, with the right-hand end 21a of the armature ingood magnetic relationship to the pole 26a, and with the left-hand end27b of the armature overlapping the pole 26b by at least 10 and spacedfrom the pole 26a. This results in magnetic flux passing through thearmature in such manner that the end 21a is of a north polarity and theend 21b of a south polarity. As the piston moves down therotor isturned15 or 20 clockwise (again speaking with respect to Figure 3) of thisposition until the end 211) of the armature is in magnetic relationshipwith the pole 26a and spaced from the pole 26b, while the other end 21aof the armature is in good magnetic relation with the pole 26b andspaced from the pole 26a. When the roller 3| gets beneath the lower endof the member 32 on the side of the piston, the movement of theactuating means, under the influence of the springs, causes a suddencounter-clockwise movement of the rotor for 15 or 20, back to theinitial position described, this resulting in a complete reversal offlux through the armature. At the moment when the reversal of fluxthrough the armature creates the maximum current in the primary 28a,(now referring particularly to Figure 6) a stud member 38 mounted on andmoved by the rotor shaft 29 contacts a spring member 39 and effectsseparation of the breaker points wand 40?), the sudden collapse of fieldaround the primary then creating a surge of high potential energy (ofthe order of 10,000 volts) in the secondary 28!), this being deliveredthrough the high potential cable 4| to the hot" electrode of the sparkplug H, the central elec-' trade. This surge of energy causes sparkingbetween the electrodes of the spark plug to ignite the combustiblecharge in the cylinder and drive the piston down on its next workingstroke. The ignition circuit is completed through ground in conventionalmanner (in this case the body of the hammer), and a condenser 42 servesto minimize arcing at the breaker points. The entire assembly provides amagneto arrangement which can be very satisfactorily actuated from afree piston without undue wear and pounding on the parts, with anignition system which can be completely sealed in so that the magneto isprotected from dust and the like. This provides a satisfactory andusable ignition system for an internal combusion hammer of thefree-piston type, actuating a magneto without the presence of a crankshaft and being capable of withstanding the tremendous vibration presentin such a hammer. The advantages of a self-contained ignition system ofthis type are obvious as it obviates the necessity for storage batteriesand cables for ignition power, as has heretofore customarily been thecase.

Another embodiment of my inventions providing magneto ignition for aninternal combustion hammer of the free-piston type is illustrated inFigure '7. In order to keep this specification as brief as possibleconsistent with a good disclosure,

reference numerals 50 higher than those hereto fore used will be appliedto parts analogous to those described in connection with Figures 1-6, sothat reference back to the earlier portions of the specification may bemade if desired to supplement the description of the form partiallyillustrated in Figure 7.

The hammer body again comprises a cylinder here identified as 60, thiscylinder having a piston BI freely reciprocable therein, a combustiblecharge being supplied to the space above the piston and ignited at anappropriate time by ignition means including the spark plug 61, thisresulting in the downward or working stroke of the piston, the returnstroke being effected by a return stroke or rebound. In this case themagneto, indicated in general as B, is mounted in the upper part of thehammer and is of the type including a laterally or lineally movablearmature 11 associated with a pole structure 16 of the permanent magnettype and providing pole faces 16a '6 member IN. The lower end of themovable member I is provided at one side here shown and 16b, this typeof magneto being analogous,

.to that described more fully in my above-menmagnetic polarity, thearmature in the position shown will have its right-hand end (speakingWith respect to the position in which the parts are viewed in Figure 7)of a south magnetic polarity, the return magnetic circuit being throughthe body of the hammer; whereas when the armature member move upwardlyuntil it has a portion closely adjacent the pole face 16a and is spacedfrom the pole face 16b, the righthand end of the armature will have anorth polarity and the flux conditions will be reversed. This rapidlychanging flux condition results in creation of a substantial current inthe primary of the coil 18, which is quickly dropped from maximum tozero by .opening of the breaker points to be hereafter described,resulting in the high voltage output from the secondary.

The armature I1 is mounted on a sleeve mem- I ber I00 verticallyslidable on a tube member IOI, this member in turn being vertically orlongitudinally movable in suitable bearings I02 and I03 to the hammerbody and having its lower end in constant engagement with the piston 8|to move therewith, as by being welded to the piston head. The startingrod 24, normally biased to the position shown in the drawings by thespring 25, extends down through this tube member IOI so that startingmovement of the piston may be effected when desired. The mounting memberI00 also carries the'movable breaker point 90a of the pair of breakerpoints including the other point 902), this being mounted on avertically reciprocable stud I04" normally biased upwardly by the springI05, the limit of upward movement of this member being determined by theposition of the nut I04a adapted to strike the bottom of the block I06in which the stud I04 is movably mounted. The limit of movement of thepoint 901) is so adjusted that as the member I00 moves upwardly thearmature member 11 has moved away from the pole face 16b and intomagnetic relationship with the pole face 16a when the points separate,so that opening of the circuit takes place at a time of maximum currentgeneration in the primary of the magneto coil.

The mounting member I00 is normally urged upwardly by a spring I01working against another upper spring I08 above the armature I7 andbetween it and a collar IOIb on the tube as the right side) with ashoulder adapted to be engaged by a latch member I00 biased inwardly bymeans here shown as a leaf spring IIO, this latch member being pivotallymounted on the pin III and bearing a roller II2'in a slot I0ld in thetube member IOI, this slot having a lower angularly arranged actuatingshoulder IOIa.

Downward movement of the piston BI carries the tube member IOI with it,downward move ment of the collar IOIb creating sufficient com-- pressionforce in the spring I00 to compress the spring I01 sufficiently to bringthe parts to the position shown in Figure 7, with the member I00helddown by the latch member I09. When the working stroke of the pistonhas been completed and it starts its return movement, no movement of themember I00 and the parts mounted thereon takes place during the majorportion of the upward movement of the piston, the only thing takingplace during this time being a reduction in the compression force of thespring -I08 until there .is practically no compression left in thisspring. As the piston 6| approaches the top limit of-its movement theshoulder portion IN a of the slot engages the roller H2 and moves thelatch member I09 out of latching engagement, whereupon a very rapidupward movement of the armature 11 takes place as a result of the forcestored in the spring I01, this resulting in generation of the desiredprimary current in the mag- .neto' and separation of the breaker pointsat the appropriate interval to provide a high potential output suppliedto the spark plug 61 and ignition of the charge in the cylinder.

While I have shown and described certain embodiments of my invention, itis to be understood that' it is capable of many modifications. Changes,therefore, in the construction and arrangement may be made withoutdeparting from thespirit and scope of the invention as disclosed in theappended claims.

I claim:

1. An internal combustion device of the freepiston type, including: acylinder adapted to have a combustible charge therein; a piston freelyreciprocable therein; electrical ignition means in one end of thecylinder; a magneto for generating a spark at said ignition means, thismagneto including a movable armature; and an actuating arrangement forthe magneto including an operating member having a portion in engagementwith said piston at all times during its reciprocation and a spring foreffecting movement of the armature, when the piston approaches said endof the cylinder, at a more rapid rate than would be effected by saidoperating means.

2. An internal combustion percussive device of the free-piston type,including: a cylinder adapted to have a combustible'charge therein; apiston freely reciprocable therein; electrical ignition means in one endof the cylinder; a magneto for generating a spark at said ignitionmeans, this magneto including a movable armature; and actuating meansfor the magneto including operating means in engagement with said pistonat all times during its reciprocation and spring means for eifectingmovement of the armature, when the piston approaches said end of thecylinder,'at a more rapid rate than would be effected by said operatingmeans. 4

3. An internal combustion percussive device of the free-piston type,including: a cylinder adapted to have a combustible charge therein; apiston freely reciprocable therein; electrical ignition means in oneend-of the cylinder; 9. magneto for generating a spark at said ignitionmeans, this magneto including a movable armature; and actuating meansfor the magneto including operating means in engagement with said pistonat all times during its reciprocation and spring means for effectingmovement of the armature, when the piston approaches said end of thecylinder, at a more rapid rate than would be efat all times during itsreciprocation and spring means for effecting movement of the armature,

when the piston approaches said end of the cylinder, at a more rapidrate than would be effected by said operating means, this actuatingmeans including a member movably mounted in a side wall of the cylinderand a member movably mounted on the piston.

5. An internal combustion percussive device of the free-piston type,including: a cylinder adapted to have a combustible charge therein; apiston freely reciprocable therein; electrical ignition means in one endof the cylinder; a magneto for generating a spark at said ignitionmeans, this magneto including a movable armature; and an actuatingarrangement for the magneto including an operating member having a.portion in engagement with said piston at all times during itsreciprocation and a spring for effecting movement of the armature, whenthe piston approaches said end of the cylinder, at a more rapid ratethan would be effected by said operating means, this actuatingarrangement including a member movably mounted in a side wall of thecylinder for pivotal movement about an axis parallel to that of thecylinder and a member mounted on the piston for limited pivotal movementabout an axis tranverse to that of the cylinder and adapted to beengaged by an end of the first mentioned member.

6. An internal combustion percussive device of the free-piston type,including: a cylinder adapted to have a combustible charge therein; apiston freely re'ciprocable. therein; electrical ignition means in oneend of the cylinder; a magneto for generating a spark at said ignitionmeans, this magneto including a movable armature; and actuating meansfor the magneto including operating means in engagement with said pistonat all times during its reciprocation and spring means for effectingmovement of the armature, when the piston approaches said end of thecylinder, at a more rapid rate than would be effected by said operatingmeans, this actuating means including a member connected to said pistonand longitudinally movable through an end wall of Said cylinder.

7. An internal combustion percussive device of the free-piston type,including: a cylinder adapted to have a combustible charge therein; apiston freely reciprocable therein; electrical ignition means in one endof the cylinder; a magneto for generating a spark at said ignitionmeans, this magneto including a movable armature; and actuating meansfor the magneto including operating means in engagement with said pistonat all times during its reciprocation and spring means for effectingmovement of the armature, when the piston approaches said end of thecylinder, at a more rapid rate than would be effected by said operatingmeans, this actuating means including a member connected to said pistonand longitudinally movable through an end wall of said cylinder andlatch means adapted to be tripped by said longitudinally movable member.

8. An internal combustion percussive device of the free-piston type,including: a cylinder adapted to have a combustible charge therein; apiston freely reciprocable therein; electrical ignition means in one endof the cylinder; a magneto for generating a spark at said ignitionmeans, this magneto including a movable armature; a spring for effectingmovement of the armature; latch means for the spring; and an operatingmember having a portion in engagement with said piston at all timesduring its reciprocation, the construction and arrangement being suchthat the operating means sets and latches the spring in one direction ofpiston movement and trips the latch in the other direction of pistonmovement when it approaches said end of the cylinder,

FRANCIS N. BARD.

REFERENCES CITED The following references are of record in the file ofthis patent:

, UNITED STATES PATENTS Fitch NOV. 2, 1943

